newlocale(3) — Linux manual page


NEWLOCALE(3)              Linux Programmer's Manual             NEWLOCALE(3)

NAME         top

       newlocale, freelocale - create, modify, and free a locale object

SYNOPSIS         top

       #include <locale.h>

       locale_t newlocale(int category_mask, const char *locale,
                          locale_t base);

       void freelocale(locale_t locobj);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       newlocale(), freelocale():
           Since glibc 2.10:
                  _XOPEN_SOURCE >= 700
           Before glibc 2.10:

DESCRIPTION         top

       The newlocale() function creates a new locale object, or modifies an
       existing object, returning a reference to the new or modified object
       as the function result.  Whether the call creates a new object or
       modifies an existing object is determined by the value of base:

       *  If base is (locale_t) 0, a new object is created.

       *  If base refers to valid existing locale object (i.e., an object
          returned by a previous call to newlocale() or duplocale(3)), then
          that object is modified by the call.  If the call is successful,
          the contents of base are unspecified (in particular, the object
          referred to by base may be freed, and a new object created).
          Therefore, the caller should ensure that it stops using base
          before the call to newlocale(), and should subsequently refer to
          the modified object via the reference returned as the function
          result.  If the call fails, the contents of base remain valid and

       If base is the special locale object LC_GLOBAL_LOCALE (see
       duplocale(3)), or is not (locale_t) 0 and is not a valid locale
       object handle, the behavior is undefined.

       The category_mask argument is a bit mask that specifies the locale
       categories that are to be set in a newly created locale object or
       modified in an existing object.  The mask is constructed by a bitwise
       LC_TELEPHONE_MASK, and LC_TIME_MASK.  Alternatively, the mask can be
       specified as LC_ALL_MASK, which is equivalent to ORing all of the
       preceding constants.

       For each category specified in category_mask, the locale data from
       locale will be used in the object returned by newlocale().  If a new
       locale object is being created, data for all categories not specified
       in category_mask is taken from the default ("POSIX") locale.

       The following preset values of locale are defined for all categories
       that can be specified in category_mask:

              A minimal locale environment for C language programs.

       "C"    Equivalent to "POSIX".

       ""     An implementation-defined native environment corresponding to
              the values of the LC_* and LANG environment variables (see

       The freelocale() function deallocates the resources associated with
       locobj, a locale object previously returned by a call to newlocale()
       or duplocale(3).  If locobj is LC_GLOBAL_LOCALE or is not valid
       locale object handle, the results are undefined.

       Once a locale object has been freed, the program should make no
       further use of it.

RETURN VALUE         top

       On success, newlocale() returns a handle that can be used in calls to
       duplocale(3), freelocale(), and other functions that take a locale_t
       argument.  On error, newlocale() returns (locale_t) 0, and sets errno
       to indicate the cause of the error.

ERRORS         top

       EINVAL One or more bits in category_mask do not correspond to a valid
              locale category.

       EINVAL locale is NULL.

       ENOENT locale is not a string pointer referring to a valid locale.

       ENOMEM Insufficient memory to create a locale object.

VERSIONS         top

       The newlocale() and freelocale() functions first appeared in version
       2.3 of the GNU C library.

CONFORMING TO         top


NOTES         top

       Each locale object created by newlocale() should be deallocated using

EXAMPLES         top

       The program below takes up to two command-line arguments, which each
       identify locales.  The first argument is required, and is used to set
       the LC_NUMERIC category in a locale object created using newlocale().
       The second command-line argument is optional; if it is present, it is
       used to set the LC_TIME category of the locale object.

       Having created and initialized the locale object, the program then
       applies it using uselocale(3), and then tests the effect of the
       locale changes by:

       1. Displaying a floating-point number with a fractional part.  This
          output will be affected by the LC_NUMERIC setting.  In many
          European-language locales, the fractional part of the number is
          separated from the integer part using a comma, rather than a

       2. Displaying the date.  The format and language of the output will
          be affected by the LC_TIME setting.

       The following shell sessions show some example runs of this program.

       Set the LC_NUMERIC category to fr_FR (French):

           $ ./a.out fr_FR
           Fri Mar  7 00:25:08 2014

       Set the LC_NUMERIC category to fr_FR (French), and the LC_TIME cate‐
       gory to it_IT (Italian):

           $ ./a.out fr_FR it_IT
           ven 07 mar 2014 00:26:01 CET

       Specify the LC_TIME setting as an empty string, which causes the
       value to be taken from environment variable settings (which, here,
       specify mi_NZ, New Zealand Māori):

           $ LC_ALL=mi_NZ ./a.out fr_FR ""
           Te Paraire, te 07 o Poutū-te-rangi, 2014 00:38:44 CET

   Program source
       #define _XOPEN_SOURCE 700
       #include <stdio.h>
       #include <stdlib.h>
       #include <locale.h>
       #include <time.h>

       #define errExit(msg)    do { perror(msg); exit(EXIT_FAILURE); \
                               } while (0)

       main(int argc, char *argv[])
           char buf[100];
           time_t t;
           size_t s;
           struct tm *tm;
           locale_t loc, nloc;

           if (argc < 2) {
               fprintf(stderr, "Usage: %s locale1 [locale2]\n", argv[0]);

           /* Create a new locale object, taking the LC_NUMERIC settings
              from the locale specified in argv[1] */

           loc = newlocale(LC_NUMERIC_MASK, argv[1], (locale_t) 0);
           if (loc == (locale_t) 0)

           /* If a second command-line argument was specified, modify the
              locale object to take the LC_TIME settings from the locale
              specified in argv[2]. We assign the result of this newlocale()
              call to 'nloc' rather than 'loc', since in some cases, we might
              want to preserve 'loc' if this call fails. */

           if (argc > 2) {
               nloc = newlocale(LC_TIME_MASK, argv[2], loc);
               if (nloc == (locale_t) 0)
               loc = nloc;

           /* Apply the newly created locale to this thread */


           /* Test effect of LC_NUMERIC */

           printf("%8.3f\n", 123456.789);

           /* Test effect of LC_TIME */

           t = time(NULL);
           tm = localtime(&t);
           if (tm == NULL)

           s = strftime(buf, sizeof(buf), "%c", tm);
           if (s == 0)

           printf("%s\n", buf);

           /* Free the locale object */

           uselocale(LC_GLOBAL_HANDLE);    /* So 'loc' is no longer in use */


SEE ALSO         top

       locale(1), duplocale(3), setlocale(3), uselocale(3), locale(5),

COLOPHON         top

       This page is part of release 5.08 of the Linux man-pages project.  A
       description of the project, information about reporting bugs, and the
       latest version of this page, can be found at

Linux                            2020-06-09                     NEWLOCALE(3)

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